pizza oven becomes a kiln

[david s]

Re: pizza oven becomes a kiln

Thanks for the details. So did using crushed firebricks make the brew noticeably lighter? or you were making a compromise of weight reduction versus strength so that you eventually chose 35 mm walls?

Yes, way lighter because the bits of crushed firebrick contain lots of air. But you can't have it both ways, it makes the end product much weaker. What you gain in lowering thermal mass and Increasing insulation, you lose in strength. But for a pottery kiln you are not throwing logs into it so strength is of less significance. I could have made the walls thicker for more strength too, but the same applies, it then just increases the thermal mass.

[david s]

Re: pizza oven becomes a kiln

I need to have a weatherproof cover over the kiln and have come up with this Gaudi inspired solution, based on catenary arches. I plan to build a skeleton of 8 mm round steel bar covered in layers of chicken wire over which I will apply a cement render.

[Gulf]

Re: pizza oven becomes a kiln

Ferrocrete! That's going to be very nice, David. I hope that you will post pics during each stage of the build.

[david s]

Re: pizza oven becomes a kiln

Ferrocrete! That's going to be very nice, David. I hope that you will post pics during each stage of the build.

Yeah, will do. I've dug the holes and welded most of the steel rod in place prior to attaching the mesh.

[david s]

Re: pizza oven becomes a kiln

Having cut and welded the main members in position (see arc formation on wall from suspended rope to create required curve), I purchased some more steel bar, 6.5 mm this time, cheaper, easier to cut and bend. So far I've only spent around $200 on the steel, This is going to be a really cheap structure, seeing it's 3.3 m in diam. I think it will be quite economic.This was really good fun, working like a spider, (what great engineers they are). Estimating cutting , bending and welding in position with the final form in mind is a way I like to work. This was easier than it looks.
The next step will be to mesh the structure which will be the time consumer, cutting and tying layers together. (See test bit on one leg, last pic), using cement render 2.5:1 sand, cement, incl. AR glass and polypropelyne fibres.

[david s]

Up she goes. I've had a lot on my plate and this project has not been a top priority, but I try to fit in an hour or so here and here. Attaching the layers of chicken wire was way more time consuming than I thought. The stuff needs to be sewn together using fine tie wire and while it's relatively simple , takes a long time.

The cement render needs to be done fairly quickly though. Ferro cement boats have to be rendered in one go apparently. Working with one on the inside and one on the outside it is going up pretty fast now.

[Gulf]

David,

That is such a cool project. I had missed the update and pics on post 35.

Working with one on the inside and one on the outside it is going up pretty fast now

Is the render being applied from the outside, with the person inside using something like a trowel as a backstop?

[UtahBeehiver]

David,

Like Gulf, I some how missed this project of yours, keep sending updates. You go from having one of the smallest WFOs to the large and massive concrete structure, LOL.

[david s]

David,

That is such a cool project. I had missed the update and pics on post 35.



Is the render being applied from the outside, with the person inside using something like a trowel as a backstop?

Yes Joe, that's it exactly. Applying the render from the inside is very difficult because it wants to fall off. The addition of some powdered clay, acrylic fortifier and the fine polypropylene fibres helps though. It is quite difficult, way harder than a standard rendering job where you only work from one side against a solid substate. But quite good fun and a challenging project. I hope Antonio Gaudi would be proud. I am asking him for his assistance.

[Gulf]

David,
I think that Gaudi was a little more into the "abstract" than your symmetrical arched "hex dome?" appears to be . I had guessed how you were applying the render. It only makes sense. And I had looked into ferrocrete a few years ago. I even looked at some of the boat builds that they do for college competitions. Again, that is a very cool project you have going on. Please keep up the posts and the pics.

[david s]

We visited many of Gaudi's buildings while in Barcellona earlier this year. The Sagrada Familia (cathedral) is the most magnificent building I've ever seen. Have been a Gaudi fan since Art school in the early 70's.
See my attached pics of his model catenary arches for the cathedral and an interior pic. It is like being in a rainforrest looking up at the canopy.

[UtahBeehiver]

Barcelona is on my buckle list. I can't remember what was your specialty in art school was. Mine was ceramics although I have not done any pottery work in decades. Maybe time to start again now that I am retired.

[david s]

I studied Graphic Design at art school. Then also studied ceramics part time when I became a teacher.
Barcelona is a wonderful, vibrant city. It's hard to believe Spain is having economic difficulties when you visit this great city.

[david s]

I've closed the dome at the top, but still have about the top 1/3 to render from the inside, plus do the floor. This thing is incredibly strong and is around one inch thick.

[UtahBeehiver]

Wow, all hand rendered . So is this the staging area for your kiln?